It has been well known a laser printer as a color image forming apparatus that is capable of forming a color image by electrophotographic method as disclosed in Japanese Patent Application Publication No. 2001-5360. For example, in a direct transfer type laser printer, an electrostatic latent image formed on a photosensitive body corresponding to respective colors is developed to form toner images by toner of the respective colors on a developing roller provided as a part of a developing device.
Then, a sheet is conveyed by an endless conveying belt to face and contact each photosensitive body and the toner images are transferred onto the sheet to form a color image thereon. Note that, a foreign matter such as toner adhering to the conveying belt is collected by a collecting member provided to confront the surface of the conveying belt at a position different from positions at which each photosensitive drum contacts the conveying belt.